Life styles in developed countries induce lack of physical exercise and excess of calories intake. As a result, people living in those countries tend to become obese. Obesity is caused by taking into the body an excessive of energy over the energy consumed by the body, and accumulation of the excessive energy as neutral fat in white adipocytes.
Obesity readily triggers diseases whose incidences are higher in developed countries, such as myocardial infarction, arteriosclerosis, and insulin resistance. Therefore, obesity is a serious problem in developed countries from the viewpoint of prevention of these diseases.
Meanwhile, neutral fat is readily accumulated as so-called subcutaneous fat, particularly in local sites such as the abdomen corresponding to the intestines, waist, buttocks, and thighs. Such fat accumulation results in a very unfavorable body shape. Furthermore, accumulation of water and waste matter in adipocytes leads to formation of cellulite, which makes the skin surface dimpled or uneven. Since cellulite imparts a cottage cheese-like texture to the skin, it is not preferred from the aesthetic viewpoint.
One known mechanism of stimulating lipolysis in the body includes activation of adenylate cyclase, and increase of cAMP (cyclic adenosine monophosphate) level in adipocytes by inhibiting PDE (phosphodiesterase) to prevent cAMP from degradation.
For example, through taking in a xanthine derivative that has a PDE inhibitory action; such as caffeine or theophylline, hormones acting on the sympathetic nerves such as noradrenalin and adrenalin are activated, whereby lipolysis is stimulated (see Patent Documents 1 and 2).
Moreover, plants containing caffeine; such as coffee beans, green tea, oolong tea, and mate tea, are known to have a lipolysis-stimulating action. Meanwhile, a plant Huang Hua Cai is known as a flower of Hemerocallis plicata Stepf, and has a diuretic action and an edema-ameliorating action. In addition to these actions, Huang Hua Cai has been recently reported to have a lipolysis-stimulating action (see Patent Document 3).
Patent Document 1: JP-A-53-059039
Patent Document 2: JP-A-08-026962
Patent Document 3: JP-A-2005-060366